Directional control valve with priority flow divider



1963 w. T.CLEMINSHAW ETAL 3,415,265

DIRECTIONAL CONTROL VALVE WITH PRIORITY FLOW DIV IDER Filed March 3, 1966 INVENTORS WILL/AM I CLEM/NSHAW PHILLIP E. ROBINSON 2 BY MMW I8 24 4 J ATTORNEYS United States Patent 3,415,265 DIRECTIONAL CONTROL VALVE WITH PRIORITY FLOW DIVIDER I William T. Cleminshaw, Cleveland, and Phillip E. Robinson, Cleveland Heights, Ohio, assignors to Parker-Hanniiin Corporation, Cleveland, Ohio, a corporation of Ohio Filed Mar. 3, 1966, Ser. No. 531,575 16 Claims. (til. 137117) ABSTRACT OF THE DESCLOSURE A directional control valve assembly having a spool containing a flow control orifice in the path of fluid flow established by movement of the spool to an operating position communicating a motor passage with a pressure feed passage, and a flow control valve member which, upon predetermined pressure drop across the flow control orifice, is moved thereby to open communication between the pressure feed passage and a return passage to divert excess fluid flow to the return passage.

The present invention relates generally as indicated to a directional control valve with priority flow divider and more particularly to a spool type directional control valve for a fluid motor having a flow control valve associated therewith to control the rate of actuation of the fluid motor when the directional control valve is in operating position.

It is a primary object of this invention to provide a spool type directional control valve of compact construction having a flow control valve contained within the valve spool.

It is another object of this invention to provide a directional control valve of the character indicated in which the aforesaid flow control valve further constitutes a check valve to prevent fluid mot-or reversal in the event of reduction in motor actuating pressure.

Other objects and advantages of the present invention will become apparent as the following description proceeds.

To the accomplishment of the foregoing and related ends, the invention, then, comprises the features hereinafter fully described and particularly pointed out in the claims, the following description and th annexed drawing setting forth in detail a certain illustrative embodiment of the invention, this being indicative, however, of but one of the various ways in which the principle of the invention may be employed.

In said annexed drawings:

FIG. 1 is a cross-section view of a directional control valve embodying the present invention, such section having been taken in a plane pasing through the axes of the valve spools therein; and

FIG. 2 is an enlarged fragmentary cross-section view showing a flow control valve disposed in a valve spool.

Referring now more particularly to the drawing, the directional control valve assembly 1 comprises a housing 2 having bores 3 and 4 in which the respective valve spools 5 and 6 are axially movable to control fluid motors (not shown) that are operatively connected with the respective motor passages 7;7 and 8;8, said motor passages 7;7 and 8;8 intersecting the respective bores 3 and 4. Also, intersecting the bores 3 and 4 are (a) a bypass passage 9 which at its upstream end communicates with the pressure inlet port 10 and which at its downstream end communicates with the return port 11; (b) pairs of pressure feed passages 12;12 and 14;14 adjacent the respective motor passages 7;7 and 8:8; and (c) return passages 15;l5 adjacent the motor passages 7;7 and 8;8 and leading to 3,415,265 Patented Dec. 10, 1968 said return port 11 at the downstream end of the bypass passage 9.

The circuit shown in the drawing is a parallel circuit in which the pressure feed passages 12;12 (with check valves 16;16 therein) and 14;14 are communicated with the portion 17 of the bypass passage 9 which is upstream with respect to both spools 5 and 6, whereby the spools 5 and 6 may be operated independently or simultaneously. Of course, if it were desired to provide for series-parallel operation, the pressure feed passages 14;14 would be communicated with the portion of the bypass passage 9 which is between the bores 3 and 4 and, in that case, the spools 5 and 6 may be operated independently but not simultaneously, since when the upstream spool 5 is shifted to an operating position, the portion of the bypass passage 9 which is downstream thereof is closed and no fluid under pressure will then be conducted to the pressure feed passages 14;14 of the downstream spool 6.

In the present case, the spool 5 may be of conventional four-way type which, when in neutral position as shown, blocks fluid communication of both motor passages 7;7 with the adjacent pressure feed and return passages 12;12 and 1.5;15 and the bypass passage 9 is opened therethrough, whereby when the other spool 6 is likewise in neutral position, fluid freely flows through the bypass passage 9 from the inlet port 10 to the return port 11.

When the spool 5 is shifted axially, one motor passage 7 is communicated with the adjacent pressure feed passage 12 and the other motor passage 7 is communicated with the adjacent return passage 15 whereby a fluid motor connected to the motor passages 7;7 will be operated in a desired direction according to which one of the motor passages 7;7 is then in communication with its adjacent pressure feed passage 12.

The spool 6 likewise is herein shown as being of a four-way type but it is of hollow construction at its opposite end portions and has three sets of openings 18, 19 and 20 in each end portion. Screwed into each end of said spool 6 is a valve guide retainer 21 which engages the valve guide member 23 along which the tubular valve member 24 is movable into and out of engagement with the seat 25 (see FIG. 2), the valve member 24 being biased toward seated position by a spring 26. The valve guide member 23 is closed at its axially inner end and has openings 27 near said closed end which are covered by the tubular valve'member 24 when in seated position. The openings 27 intersect the bore 28 for flow of fluid therethrough to the adjacent return passage 15 via the openings 29 and 20.

Thus, when the spool 6 is shifted downwardly from the neutral position shown, the tubular valve member 24 operates as a check valve to permit flow of fluid from the upper feed passage 14 to the adjacent motor passage 8 through the openings 18 and 19 in the spool 6, the rate of flow 'being controlled by the annular orifice 30 (see FIG. 2) defined between the outside diameter of the tubular valve member 24 and the surrounding bore of the spool 6. When the pressure drop across such annular ori free 30 reaches a predetermined value as determined by the biasing spring 26, the lower end of the tubular valve member 24 will progressively uncover the openings 27 in the lower end of the valve guide member 23 whereby excess fluid will be returned to the upper return passage 15 via such openings 27, bore 28, and openings 29 and 20 in the valve guide member '23 and spool 6. 1n the downwardly shifted position of the spool 6, the fluid displaced by the fluid motor operatively connected to the motor passages 8;8 is conducted from the lower motor passage 8 to the adjacent return passage 15 via the openings 18, the annular orifice 30, and the openings 19. Here again if the pressure drop of the returning fluid across the orifice 30 predeterminedly exceeds the force exerted by spring 26, the valve member 24 will uncover the openings 27 of the lower valve guide member 23 for flow to the return passage via the bore 28 and openings 29 and When the spool 6 is shifted upwardly from the FIG. 1 neutral position the lower motor passage 8 will be communicated with the adjacent pressure feed passage 14 and the upper motor passage 8 will be communicated with the adjacent return passage 15 and the flow control valves will operate as described above.

From the foregoing, it can be seen that the directional control valve assembly 1 herein provides for division of flow on the pressure side of the circuit for establishing only a predetermined flow from the pressure feed and motor passages 8 and 14 that are in fluid communication with each other, with excess fluid being returned or diverted to the adjacent return passage 15.

It is to be noted that the flow control or flow divider valves also operate as load check valves so that in the event of reduction in fluid pressure in a pressure feed passage 14 to a valve less than in the motor passage 8 then in communication therewith, there will be no back flow of fluid.

Other modes of applying the principle of the invention may be employed, change being made as regards the details described, provided the features stated in any of the following claims, or the equivalent of such, be employed.

We therefore particularly point out and distinctly claim as our invention:

1. A directional control valve assembly cimprising a housing having a bore intersected axially therealong by a pressure feed passage for connection with a fluid pressure source, by a motor passage for connection with a fluid motor, and by a return passage for connection with a reservoir; a valve spool movable in said bore to at least one operating position whereat said feed passage is communicated with said motor passage; said assembly having a flow control orifice in the path of fluid flow when said spool is in said one operating position; said spool having a movable flow control valve member which, upon predetermined pressure drop across said flow control orifice, is moved thereby to open communication between said pressure feed passage and said return passage to divert excess fluid flow to said return passage; said flow control valve member being movable in a bore in said spool; said spool having first, second, and third lateral openings leading to said bore in said spool and respectively communicating with saidpressure feed, motor, and return passages in said one operating position of said spool; said flow control orifice being between said first and second openings; said flow control valve member, when moved as aforesaid, opening communication between said first and third openings.

2. A directional control valve assembly comprising a housing having a bore intersected axially therealong by a pressure feed passage for connection with a fluid pressure source, by a motor passage for connection with a fluid motor, and by a return passage for connection With a reservoir; a valve spool movable in said bore to at least one operating position whereat said feed passage is communicated with said motor passage; said assembly having a flow control orifice in the path of fluid flow when said spool is in said one operating position; said spool having a bore, a flow control valve member disposed in the bore of said spool movable in response to predetermined pressure drop across said flow control orifice; and a guide for said flow control valve member having an opening which is uncovered by such movement of said flow control valve member to establish communication between said pressure feed passage and said return passage to divert excess fluid flow to said return passage.

3. A flow control valve comprising a body having a bore, and an inlet passage and two outlet passages leading to said bore; a pressure actuated flow control valve member movable in said bore and defining therewith a flow control orifice between said inlet passage and one outlet passage; a guide for said flow control valve member having an opening covered by said flow control valve member to close communication between the other outlet passage and said inlet passage when the pressure drop across said orifice is less than predetermined value and uncovered for establishing communication between said other outlet passage and said inlet passage upon movement of said flow control valve under the influence of a pressure drop across said orifice exceeding such predetermined value, whereby excess fluid flow is diverted from said inlet passage to said other outlet passage.

4. The flow control valve of claim 3 wherein said body comprises the spool of a directional control valve in which said inlet, one, and other outlet passages are respectively communicated with the pressure feed, motor, and return passages of said directional control valve.

5. The assembly of claim 1 wherein a guide for said flow control valve member is disposed in the bore of said spool and is provided with an opening which is uncovered by such predetermined movement of said flow control valve member to communicate said first and third openings with each other when said spool is in said one operating position.

6. The assembly of claim 1, wherein, in another operating position of said spool, said motor passage is communicated with said return passage via said first and second openings and said flow control orifice.

7. A directional control valve assembly comprising a housing having a bore intersected axially therealong by bypass, pressure feed, motor, and return passages; a fourway open center directional control valve spool axially movable in said bore to provide a neutral position whereat said bypass passage is open and communication is blocked thereby between two motor passages and associated pressure feed and return passages and to provide two operating positions whereat said bypass passage is closed and a pressure feed passage is selectively communicated with either one of said two motor passages while the other one of said two motor passages is communicated with a return passage thus to control actuation of a double-acting fluid motor adapted to be connected to said two motor passages; said assembly having a flow control orifice in the path of fluid flow from a pressure feed passage to a motor passage when said spool is in one of said operating positions; said spool having a movable flow control valve member which, upon predetermined pressure drop across said flow control orifice in said one operating position of said spool, is moved thereby to open comunication between said pressure feed passage and a return passage to divert excess fluid flow to said return passage.

8. The assembly of claim 7, wherein said assembly has a second flow control orifice which is in the path of fluid flow from a pressure feed passage to the other one of said two motor passages when said spool is in the other of said operating positions; and wherein said spool has a second movable flow control valve member which, upon predetermined pressure drop across said second flow control orifice, is moved to open communication between said pressure feed passage and said return passage to divert excess fluid flow to said return passage when said spool is in said other operating position.

9. The assembly of claim 7 wherein said spool has a passage which, in said one operating position, leads to said return passage and which is opened to said feed passage upon such movement of said flow control valve member.

10. The assembly of claim 7 wherein spring means biases said flow control valve member in a direction closing communication between said pressure feed passage and said return passage when the pressure drop across said flow control orifice is less than such predetermined value.

11. The assembly of claim 7 wherein said fiow control valve member moves to close communication between said motor passage and said pressure feed passage as when the fluid pressure in said feed passage is less than in said motor passage.

12. The assembly of claim 7 wherein said flow control valve member, in said other operating position of said spool, permits flow of fluid to a return passage via said flow control orifice.

13. The assembly of claim 7 wherein said flow control valve member is movable in a bore in said spool and defines therewith said flow control orifice.

14. The assembly of claim 7 wherein said flow control valve member is movable in a bore in said spool; wherein said spool has first, second, and third lateral openings leading to said bore in said spool and respectively communicating with said pressure feed, motor, and return passages in said one operating position of said spool; said flow control orifice being between said first and second openings; and wherein said flow control valve member, when moved as aforesaid, opens communication between said first and third openings.

15. The assembly of claim 14 wherein a guide for said flow control valve member is disposed in the bore of said spool and is provided with an opening which is uncovered by such predetermined movement of said flow control valve member to communicate said first and third openings with each other when said spool is in said one operating position.

16. The assembly of claim 14 wherein, in said other operating position of said spool, the aforesaid motor passage is communicated with a return passage via said first and second openings and said flow control orifice.

References Cited UNITED STATES PATENTS 6/1965 Peach 137--625.68 XR 8/1965 Beutler 137596 

